The invention relates to a combustion engine with one or more cylinders, which are lined with liners, which are produced from steel by deep drawing or by deformation by compression.
From methods for repairing, in particular, large engines and those, for which the crankcase is cast in one piece with the cylinders, the idea was developed, for reasons of costs, of using cylinder liners. The worn or damaged cylinders are drilled out, provided that the wall thickness permits such a procedure, and the cast cylinder liner, the bore of which corresponds to the original, is then inserted, so that the pistons can continue to be used.
There are also engine constructions, for which cylinder liners are inserted from the very start as an exchangeable part (DE 4029427 A1). In general, these cylinder linings are produced by the centrifugal casting method and have a wall thickness of 2.5 to 3.5 mm. The liner is pushed in without external finishing and honed on its running surface to fit to the piston diameter.
Such measures do not come into consideration for inexpensive engines, such as small one-cylinder engines, since the costs associated therewith are too high in relation to the total costs of a new cylinder block or a new engine.
However, from the point of view of preserving raw materials, it is desirable to line small engines, instead of having to discard them after they are worn out.
Accordingly, it is an object of the present invention to make the repair even of inexpensive engines meaningful from an economic point of view.
A known, particularly thin-wall liner (U.S. Pat. No. 2,229,671) requires that the manufacturing process be highly accurate, since the liners are inserted dry into the cylinder bore. In this connection, it is important to realize a gap-free press fit in order to achieve undisturbed conduction of heat. This fit is achieved using a certain flexibility of the liner wall, which has a very small thickness. After the known liner is inserted into the cylinder bore, its running surface is lapped.